## Math 6 Chapter 3 Lesson 17: Percentage chart

## 1. Summary of theory Tóm

### 1.1. Column chart

A vertical number ray is constructed. Each unit length on the number ray corresponds to 1%.

To represent a ratio a percent, we construct a rectangular column whose height is a unit of length on the number line.

**Example 1:**

### 1.2. Square chart

A square is divided into 100 equal small squares.

To represent a ratio a percent, a small square is bolded.

**Example 2:**

### 1.3. Fan chart

One divides a circle into 100 equal fan shapes (by radii).

To represent a percentage, a contiguous fan is bolded.

**Example 3:**

## 2. Illustrated exercise

**Question 1: **To go from home to school, out of 40 students in grade 6B, 6 take the bus, 15 ride a bicycle, and the rest walk. Calculate the percentage of students in grade 6B who ride the bus, bike, or walk to the rest of the class and plot it as a bar chart.

– The percentage of students in class 6B who ride the bus to students in the whole class is: \( \displaystyle {{6,100} \over {40}} = 15\% \)

– The percentage of students in class 6B who ride bicycles to students in the whole class is: \( \displaystyle {{15,100} \over {40}} = 37.5\% \)

– The ratio of the number of students in grade 6B who walk to the whole class is:

\(100\% – (15\% + 37.5\%) = 47.5\% \)

## 3. Practice

### 3.1. Essay exercises

**Question 1:** The results of finding out the interests of 320 6th grade students showed that exactly 62.5% of the students liked football; 43.2% like shuttlecock and 25% like skipping rope. In your opinion, which number is definitely incorrect?

**Verse 2:** Work volume increased by 80% but labor productivity increased by only 20%. By what percentage will the number of workers be increased?

### 3.2. Multiple choice exercises Bài

**Question 1:** The ratio of my age to my age is 150%. I’m 4 years younger than you. Ask me how old are you?

A. 12 years old

B. 8 years old

C. 10 years old

D. 6 years old

**Verse 2:** Ratio of child and mother’s age 37.5%. The sum of their ages is 44. How old are you?

A. 28 years old

B. 30 years old

C. 32 years old

D. 34 years old

**Question 3:** Class 6C has 48 students. The number of excellent students is equal to 18.75% of the students in the whole class. The average number of students is 300% of the number of excellent students. The rest are good students. Ask class 5C how many students on average?

A. 24

B. 27

C. 12

D. 9

**Question 5:** Class 6C has 48 students. The number of excellent students is equal to 18.75% of the students in the whole class. The average number of students is 300% of the number of excellent students. The rest are good students. Calculate the ratio of the number of average students and the number of good students to the total number of students?

A. 25%

B. 35%

C. 45%

D. 60%

**Question 5: **Calculate the mass of sugar contained in \(\frac{3}{4}\) tons of fresh cassava knowing that fresh cassava contains 25% sugar.

A. 187.5 kg

B. 18.75 kg

C. 1,875 kg

D. 0.1875 kg

## 4. Conclusion

Through this lesson, you should know the following:

- Know the types of charts.
- Do some chart-related exercises.

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